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You searched for +publisher:"University of Saskatchewan" +contributor:("Fretz, Peter B."). Showing records 1 – 2 of 2 total matches.

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University of Saskatchewan

1. Allen, Andrew Lyndon. Investigations into congenital hypothyroidism of foals.

Degree: 1996, University of Saskatchewan

A naturally occurring disease involving hyperplasia of the thyroid gland and a consistent pattern of musculoskeletal deformities of newborn foals in western Canada was first described in 1981. This disease was an important cause of foal mortality and, therefore, reproductive loss throughout western Canada during the 1990s and has since been recognized in western Ontario and the northwestern United States. A series of investigations were conducted to describe, characterize, and attempt to determine the pathogenesis and cause of this syndrome. Affected foals were typically born after a long gestation (x = 360 days, range = 340 to 400 days), were diagnosed as hypothyroid based on a poor response to the administration of thyroid-stimulating hormone, and had various musculoskeletal lesions of which mandibular prognathism, flexural deformities and rupture of tendons of the limbs, and incomplete ossification of the carpal and tarsal bones were present most commonly. In spite of the normal to long gestation, foals had signs of immaturity, were usually weak and unable to stand, became septic, and died or were euthanatised. Similar histories, clinical findings, and lesions were present in surgically created hypothyroid foals that were thyroidectomized in utero at about 210 days gestation. These findings supported the conclusion that foals which naturally developed these lesions were also hypothyroid in utero and that all the lesions present in affected foals were the result of the hypothyroidism and not of an underlying concurrent disease process. A case-control study was conducted to identify risk factors for naturally occurring congenital hypothyroidism. Information from congenitally hypothyroid foals concerning foal and dam signalment, farm environment, and dam management was compared with that from normal foals. Pregnant mares fed greenfeed, not supplemented with mineral, that left their "home farm" during gestation, or grazed irrigated pasture, had a 13.1 (P=0.0068), 5.6 (P=0.0472), 4.3 (P=0.0076) and approximately 15.3 (P=0.0245) times greater odds, respectively, of producing a congenitally hypothyroid foal than mares not exposed to these factors. Greenfeed often contains high levels of nitrate (NO3-) which is known to impair thyroid gland function. In light of this, forage samples from participating farms were analysed for nitrate levels. The odds of one or more congenitally hypothyroid foal being born on a farm feeding forage with at least a trace of nitrate was 8.0 times greater (P=0.0873) than the odds of the disease occurring a farm that fed forage free of nitrate. Further, the odds of a mare producing an affected foal when fed forage containing at least a trace of nitrate was 5.9 times greater (P=0.0007) than a mare fed nitrate-free forage.This study suggests that congenital hypothyroidism in foals may result from diets containing nitrate or low in iodine being fed to pregnant mares. These results need to be confirmed through further field investigations and controlled experiments.… Advisors/Committee Members: Riddell, Craigmyle, Fretz, Peter B..

Subjects/Keywords: veterinary pathology; equine pathology; horses - diseases; TH-MSD syndrome; thyroid gland hyperplasia; horses - neonatal development; foals - hypothyroidism

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Allen, A. L. (1996). Investigations into congenital hypothyroidism of foals. (Thesis). University of Saskatchewan. Retrieved from http://hdl.handle.net/10388/etd-10212004-000356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Allen, Andrew Lyndon. “Investigations into congenital hypothyroidism of foals.” 1996. Thesis, University of Saskatchewan. Accessed August 04, 2020. http://hdl.handle.net/10388/etd-10212004-000356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Allen, Andrew Lyndon. “Investigations into congenital hypothyroidism of foals.” 1996. Web. 04 Aug 2020.

Vancouver:

Allen AL. Investigations into congenital hypothyroidism of foals. [Internet] [Thesis]. University of Saskatchewan; 1996. [cited 2020 Aug 04]. Available from: http://hdl.handle.net/10388/etd-10212004-000356.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Allen AL. Investigations into congenital hypothyroidism of foals. [Thesis]. University of Saskatchewan; 1996. Available from: http://hdl.handle.net/10388/etd-10212004-000356

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation


University of Saskatchewan

2. Leach, Douglas Harold. The structure and function of the equine hoof wall.

Degree: 1980, University of Saskatchewan

Strength of the equine hoof wall was investigated by examining the relationships between measured mechanical properties and the histological and ultrastructural morphology of the hoof wall material. The keratinization of the stratum medium and primary lamellae of the stratum internum, and the method by which the wall is attached to the dermis, were also described. A model of hoof wall function was formulated by integrating information of morphology and mechanical properties. Keratinization was similar to that of hard (α) keratins, with tonofilaments being synthesized within each cell concomitant to loss of organelles and degeneration of the nucleus. Keratohyalin was not formed. Spinous cells were joined by desmosomes and gap junctions. In the inter­tubular horn of the stratum medium processes from cells of the stratum spinosum invaginated into or between adjacent cells. These processes frequently included extensive areas of gap junction attachment. Some areas of gap junction attachment appeared to be budded off from the plasmalemma, thus forming internalized annular gap junctions. These were subsequently destroyed by lysosome-like structures. In cells of the stratum spinosum located near the stratum spinosum-stratum corneum junction, non-laminated membrane-coating granules (MCG) aggregated on the periphery of the cell. Intercellular material was found which apparently resulted from extrusion of the contents of the MCG. Coincidently a third type of junction, the type 3 junction, and an intercellular line were found. In cells of the stratum corneum located near the stratum spinosum-stratum corneum junction, non-membrane bound acid phosphatase reaction product was found on the periphery of the cytoplasm. In cell layers immediately distal to this the reaction product was found in most of the intercellular space except that of the type 3 junction and intercellular line. It was therefore proposed that the establishment of the type 3 junction and intercellular line prior to leakage of acid phosphatase into the intercellular space, and the lack of permeability of these structures to this hydrolytic enzyme, created stable areas of inter­-cellular adhesion between fully keratinized cells. Stress-strain curves were obtained by compressing square hoof wall specimens in all three orthogonal directions using an Instron Universal Testing Machine. Values of modulus of elasticity, a measure of specimen rigidity, and proportional limit were determined from these curves. The water content and type and number of tubules present in each specimen was determined. Hoof wall specimens were nonhomogeneous, mechanically anisotropic and did not exhibit a yield point. Specimens from the more exterior locations of the stratum medium were stronger, drier and more anisotropic than specimens located near the stratum internum. The mechanical properties of specimens from black hooves were not significantly different from those of white hooves. The compressive strength (rigidity) of specimens loaded in a direction parallel to the hoof… Advisors/Committee Members: Fretz, Peter B., Oliphant, Lynn, Sprigings, Eric.

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APA · Chicago · MLA · Vancouver · CSE | Export to Zotero / EndNote / Reference Manager

APA (6th Edition):

Leach, D. H. (1980). The structure and function of the equine hoof wall. (Thesis). University of Saskatchewan. Retrieved from http://hdl.handle.net/10388/etd-06172009-130346

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Chicago Manual of Style (16th Edition):

Leach, Douglas Harold. “The structure and function of the equine hoof wall.” 1980. Thesis, University of Saskatchewan. Accessed August 04, 2020. http://hdl.handle.net/10388/etd-06172009-130346.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

MLA Handbook (7th Edition):

Leach, Douglas Harold. “The structure and function of the equine hoof wall.” 1980. Web. 04 Aug 2020.

Vancouver:

Leach DH. The structure and function of the equine hoof wall. [Internet] [Thesis]. University of Saskatchewan; 1980. [cited 2020 Aug 04]. Available from: http://hdl.handle.net/10388/etd-06172009-130346.

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

Council of Science Editors:

Leach DH. The structure and function of the equine hoof wall. [Thesis]. University of Saskatchewan; 1980. Available from: http://hdl.handle.net/10388/etd-06172009-130346

Note: this citation may be lacking information needed for this citation format:
Not specified: Masters Thesis or Doctoral Dissertation

.